Quarterly water-quality reports show rising salinities, winter blooms and low oyster recruitment in Indian River Lagoon
Get AI-powered insights, summaries, and transcripts
Subscribe
Summary
Scientists reported unusually dry conditions leading to higher salinities at multiple monitoring sites, continued winter bloom conditions including Aureoumbra (brown tide), no hypoxia recorded in the reporting window, and seasonally low oyster recruitment and seagrass percent cover at several transects.
At the council's Feb. 13 meeting, Lauren Hall (St. Johns River Water Management District) and Melanie Parker (South Florida Water Management District) presented Northern/Central and Southern Lagoon water-quality updates covering November 2025 through early February 2026.
Hall said the basin experienced a very dry three-month period after a rainy October and that continuous monitoring stations show salinity increases at several sites, notably Mosquito Lagoon, Vero and Titusville. "Our salinity due to this lack of rain that we've had over these last few months, we are seeing salinity increases at several of our sites throughout the lagoon," Hall said. She reported no hypoxic conditions across monitored sites during the period but noted fluctuating turbidity and a sensor she suspected might be malfunctioning.
Parker focused on the St. Lucie Estuary and the southern lagoon, reporting very low inflows (about 109 cubic feet per second from the tidal basin in the most recent week) and sharp salinity increases since November. "Stressful salinities are reaching up into the north and south forks of the estuary and really covering the core population of oysters in the estuary," Parker said, noting that oysters tolerate current colder temperatures better but that higher salinity is nonetheless a stressor. Parker added that oyster recruitment is near zero at present — a seasonal low expected in cool months after extraordinary recruitment last summer — and that seagrass percent cover at long-term transects ranged from about 1% to 9% at sampled sites.
Both presenters said bloom conditions persist in parts of the lagoon, including Aureoumbra brown tide in Southern Mosquito Lagoon, and that winter transect monitoring and 2025 draft seagrass maps will provide additional context at the next quarterly meeting.
The council did not take enforcement actions at the meeting; members asked staff to continue monitoring, to report winter-related fish and turtle strandings in subsequent updates, and to provide 2025 seagrass maps at the next quarterly meeting.